Manufacturing method of TFT array substrate, TFT array substrate and display panel

ABSTRACT

A manufacturing method of a TFT array substrate is provided, comprising: depositing and forming a gate and a gate scanning line; depositing sequentially a gate insulating layer, an active layer and a second metal layer; depositing and forming a first photoresist layer and a second photoresist layer on the second metal layer; first photoresist layer comprising a first-stage photoresist layer, second-stage photoresist layer and third-stage photoresist layer with increasing thickness, the first-stage photoresist layer being in the middle of the first photoresist layer and a channel being formed; ashing to remove first-stage photoresist layer, forming a source and a drain by etching; and ashing to remove the second-stage photoresist layer, and then depositing a passivation layer as a whole; stripping third-stage photoresist layer and second photoresist layer, depositing and forming a pixel electrode and a common electrode.

RELATED APPLICATION

The present application is a National Phase of International ApplicationNumber PCT/CN2018/090650, filed Jun. 11, 2018, and claims priority toChinese Patent Application No. 201810333074.5, entitled “manufacturingmethod of TFT array substrate, TFT array substrate and display panel”,filed on Apr. 13, 2018, the disclosure of which is incorporated hereinby reference in its entirety.

FIELD OF THE INVENTION

The present disclosure relates to a flexible display field, inparticular to a TFT array substrate and a manufacturing method thereof,and a display panel.

BACKGROUND OF THE INVENTION

Currently, TFT-LCD (Thin Film Transistor Liquid Crystal Display) hasbecome one of mainstream displays. Each liquid crystal pixel on TFT-LCDis driven by a TFT (Thin Film Transistor) integrated behind pixel, sothat the screen information can be displayed at high speed, highbrightness and high contrast. The manufacturing of TFT-LCD can beroughly divided into three processes including TFT array process, liquidcrystal unit process and liquid crystal module process, in which the TFTarray process has an important influence on the display performance of aliquid crystal panel, especially on the manufacturing cost of a panel.

In the TFT array process of manufacturing a TFT array substrate,multiple photolithography procedures in which the mask is used areindispensable, such as for a semiconductor integrated circuit board. Theprocess of manufacturing TFT array substrate has experienced thedevelopment process from 7-mask process to the present 5- or 4-maskprocess, and the 5- or 4-mask process is still the mainstream technologyfor manufacturing a TFT array substrate nowadays. An increasinglymaturing 4-mask process is formed by merging the photolithography of anactive layer and a drain into one mask using grayscale lithographytechnology on the basis of the original 5-mask process. However, therequirement for the productivity efficiency of a TFT array substrate isincreasingly strict with increasing demand for a TFT array substrate inthe display panel market. Therefore, it is necessary to develop amanufacturing process of a TFT array substrate, which can significantlysimplify the process flow and greatly improve the productivity andutilization of equipments.

SUMMARY OF THE INVENTION

In light of this, a manufacturing method of a TFT array substrate isprovided by the implementations of the present disclosure. Themanufacturing method adopts 3-mask process, which can significantlysimplify the process flow and greatly improve the productivity andutilization of equipments.

In the first aspect, the implementations of the present disclosureprovides a manufacturing method of a TFT array substrate comprising:

providing a rigid substrate, depositing a first metal layer on the rigidsubstrate, and patterning the first metal layer to form a gate electrodeand a gate scanning line;

depositing sequentially a gate insulating layer, an active layer and asecond metal layer on the gate electrode and the gate scanning line;

coating photoresist on the second metal layer and patterning thephotoresist to form a first photoresist layer and a second photoresistlayer; wherein the first photoresist layer comprises a first-stagephotoresist layer, a second-stage photoresist layer and a third-stagephotoresist layer; the thickness of the second-stage photoresist layeris larger than that of the first-stage photoresist layer, and thethickness of the third-stage photoresist layer is larger than that ofthe second-stage photoresist layer; the first-stage photoresist layer isdisposed in the middle of the first photoresist layer and a channel isformed; and the thickness of the second photoresist layer is larger thanthat of the second-stage photoresist layer;

etching a region of the second metal layer, a region of the active layerand a region of the gate insulating layer, which are outside the channeland uncovered by the first photoresist layer and the second photoresistlayer to expose the rigid substrate;

performing ashing treatment on the first photoresist layer and thesecond photoresist layer to remove the first-stage photoresist layer,and forming a source electrode and a drain electrode by etching;

performing ashing treatment on the second-stage photoresist layer, thethird-stage photoresist layer and the second photoresist layer to removethe second-stage photoresist layer, and then depositing a passivationlayer as a whole;

stripping the third-stage photoresist layer and the second photoresistlayer, and depositing a transparent conductive layer and patterning thetransparent conductive layer to form a pixel electrode and a commonelectrode.

Optionally, the active layer comprises a first amorphous silicon filmand a second amorphous silicon film sequentially stacked on the gateinsulating layer, and the first amorphous silicon film is disposedbetween the gate insulating layer and the second amorphous silicon film.

Optionally, the material of the first amorphous silicon film comprisesamorphous silicon and the material of the second amorphous silicon filmcomprises impurity ion-doped amorphous silicon.

Optionally, the process of forming a source and a drain by etchingcomprises: etching the first metal layer covered by the first-stagephotoresist layer and etching the second amorphous silicon film.

Optionally, after etching a region of the second metal layer, a regionof the active layer and a region of the gate insulating layer, which areoutside the channel and uncovered by the first photoresist layer and thesecond photoresist layer, a data line layer is formed from the secondmetal layer covered by the second photoresist layer.

Optionally, the gate scanning line and the data line layer is bridgedthrough the common electrode.

Optionally, the material of the transparent conductive layer comprisesat least one of indium tin oxide (ITO), indium oxide zinc (IZO),aluminum zinc oxide (AZO) and indium gallium zinc oxide (IGZO).

Optionally, the material of the passivation layer comprises at least oneof silicon oxide (SiO_(x)) and silicon nitride (SiN_(x)).

The manufacturing method of a TFT array substrate in the first aspect ofthe present disclosure adopts 3-mask process, and it significantlysimplifies the process flow and greatly improves the productivity andutilization of equipments, reduces production cost and can be used forlarge-scale industrial production. The TFT array substrate prepared bythe manufacturing method described herein has excellent performance andstable structure.

In the second aspect, the present disclosure provides a TFT arraysubstrate prepared by the manufacturing method as described in the firstaspect of the present disclosure. The TFT array substrate comprises arigid substrate, a gate electrode and a gate scanning line stacked onthe rigid substrate; and a gate insulating layer, an active layer, asource electrode, a drain electrode, a data line layer, a passivationlayer, a pixel electrode and a common electrode stacked sequentially onthe gate electrode and the gate scanning line. One side of the drainelectrode disclosed herein is covered with the pixel electrode; the gateinsulating layer and the active layer are disposed between the gatescanning line and the data line layer; the gate scanning line and thedata line layer are respectively connected with the common electrode.The conduction between the gate scanning line and the data line layercan be achieved conveniently by the common electrode acting as a bridgebetween them in the TFT array substrate of the second aspect in thepresent disclosure, which is beneficial to the subsequent peripherallayout and wiring.

In the third aspect, the present disclosure further provides a displaypanel comprising a TFT array substrate prepared by the manufacturingmethod as described in the first aspect of the present disclosure. Thedisplay panel further comprises a color film substrate, a liquid crystallayer, a backlight module, and the like. The advantages of the presentdisclosure will be partly explained in the following description, someof the advantages are obvious according to the description, or can beknown by the implementation of the implementations of the presentdisclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a process flow diagram illustrating a manufacturing method ofa TFT array substrate provided by an implementation of the presentdisclosure.

FIG. 2 is a schematic cross-sectional view illustrating the step S10 ina manufacturing method of a TFT array substrate provided by animplementation of the present disclosure.

FIG. 3 is a schematic cross-sectional view illustrating the step S20 ina manufacturing method of a TFT array substrate provided by animplementation of the present disclosure.

FIG. 4 is a schematic cross-sectional view illustrating the step S30 ina manufacturing method of a TFT array substrate provided by animplementation of the present disclosure.

FIG. 5 is a schematic cross-sectional view illustrating the step S40 ina manufacturing method of a TFT array substrate provided by animplementation of the present disclosure.

FIG. 6 is a part of a schematic view illustrating the step S50 in amanufacturing method of a TFT array substrate provided by animplementation of the present disclosure.

FIG. 7 is another part of a schematic view illustrating the step S50 ina manufacturing method of a TFT array substrate provided by animplementation of the present disclosure.

FIG. 8 is a part of a schematic view illustrating the step S60 in amanufacturing method of a TFT array substrate provided by animplementation of the present disclosure.

FIG. 9 is another part of a schematic view illustrating the step S60 ina manufacturing method of a TFT array substrate provided by animplementation of the present disclosure.

FIG. 10 is a part of a schematic view illustrating the step S70 in amanufacturing method of a TFT array substrate provided by animplementation of the present disclosure.

FIG. 11 is another part of a schematic view illustrating the step S70 ina manufacturing method of a TFT array substrate provided by animplementation of the present disclosure.

FIG. 12 is a partial schematic view illustrating the step S240 in amanufacturing method of a TFT array substrate provided by anotherimplementation of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

The following are preferred implementations of the present disclosure,and it should be noted that those skilled in the art can make someimprovements and embellishments without departing from the principles ofthe implementations of the present disclosure, and those improvementsand embellishments shall be within the protection scope of theimplementations of the present disclosure.

The terms “comprising” and “having”, and any variations thereofappearing in the description, the claims, and the drawings of theapplication are intended to cover non-exclusive inclusions. For example,a process, method, system, product, or device that comprises a series ofsteps or units is not limited to the listed steps or units, butoptionally further comprises unlisted steps or units, or, optionallyfurther comprises other steps or units inherent to the process, method,system, product, or device. Moreover, the terms “first”, “second”,“third”, etc. are used to distinguish different objects, and are notintended to describe a particular stage.

See FIG. 1. The present disclosure provides a manufacturing method of aTFT array substrate comprising:

S10: providing a rigid substrate, depositing a first metal layer on therigid substrate, and patterning the first metal layer to form a gateelectrode and a gate scanning line;

S20: depositing sequentially a gate insulating layer, an active layerand a second metal layer on the gate electrode and the gate scanningline;

S30: coating photoresist on the second metal layer and patterning thephotoresist to form a first photoresist layer and a second photoresistlayer; wherein the first photoresist layer comprises a first-stagephotoresist layer, a second-stage photoresist layer and a third-stagephotoresist layer; the thickness of the second-stage photoresist layeris larger than that of the first-stage photoresist layer, and thethickness of the third-stage photoresist layer is larger than that ofthe second-stage photoresist layer; the first-stage photoresist layer isdisposed in the middle of the first photoresist layer and a channel isformed; and the thickness of the second photoresist layer is larger thanthat of the second-stage photoresist layer;

S40: etching a region of the second metal layer, a region of the activelayer and a region of the gate insulating layer, which are outside thechannel and uncovered by the first photoresist layer and the secondphotoresist layer to expose the rigid substrate;

S50: performing ashing treatment on the first photoresist layer and thesecond photoresist layer to remove the first-stage photoresist layer,and forming a source electrode and a drain electrode by etching;

S60: performing ashing treatment on first photoresist layer and thesecond photoresist layer to remove the second-stage photoresist layer,and then depositing a passivation layer as a whole;

S70: stripping the third-stage photoresist layer and the secondphotoresist layer, and depositing a transparent conductive layer andpatterning the transparent conductive layer to form a pixel electrodeand a common electrode.

Specifically, as shown in FIG. 2, at S10, rigid substrate 10 isprovided, a first metal layer (M1) (not drawn) is deposited on the rigidsubstrate using physical vapor deposition (PVD) and patterned to formgate electrode 21 and gate scanning line 22 by operations of coating,exposure, developing, etching, stripping, and the like using a firstmask process. The rigid substrate can comprise an active area (AA)region and non-active area (non-AA) region, and the gate electrode islocated in AA region and the gate scanning line is in non-AA region. Inthe method of the implementation, the material of the first metal layercomprises at least one of copper (Cu), aluminum (Al), neodymium (Nd),chromium (Cr), molybdenum (Mo), titanium (Ti) and silver (Ag).Specifically, the material of the first metal layer can be copper orsilver, or the like. The material of the first metal layer can also becopper-aluminum alloy, copper-molybdenum alloy, copper-titanium alloy orsilver-molybdenum alloy, or the like. The first metal layer has lowelectrical resistance, good electrical conductivity, and hascharacteristics such as toughness and bending resistance.Correspondingly, gate electrode 21 and gate scanning line 22 have highelectrical conductivity. Optionally, the section of pattern formed byetching (such as gate electrode 21 and gate scanning line 22) is a slopsurface (such as a trapezoidal shape) so as to reduce the incidence ofcross-break, and it can effectively avoid the disconnection or break ofother film layers deposited subsequently. Optionally, the method fordepositing the first metal layer further comprises magnetron sputtering,chemical vapor deposition (CVD), etc. The etching comprises wet etchingor dry etching. Processes of cleaning, detecting, etc, can be includedin S10 without limitation.

In the implementation, the thickness and shape of gate 21 or gatescanning line 22 can be defined according to product and processrequirements. Preferably, the surface of gate electrode 21 and/or gatescanning line 22 can be provided with a layer resisting oxidation andcorrosion to improve the practical performance of the product andprolong the service life of the product. Further, after the first metallayer is patterned, a first electrode for storage of capacitance is alsoformed in addition to the formation of a gate and a gate scanning line.

As shown in FIG. 3, at S20, gate insulating layer 30 is deposited andformed on the entire surface of rigid substrate10 provided with gateelectrode 21 and gate scanning line 22 obtained at above S10; gateinsulating layer 30 completely covers gate electrode 21 and gatescanning line 22 and extends to the entire surface of rigid substrate10; then active layer 40 and second metal layer (M2) are deposited ongate insulating layer 30. Optionally, the deposition method comprises atleast one of magnetron sputtering, chemical vapor deposition andphysical vapor deposition. Preferably, gate insulating layer 30 andactive layer 40 are continuously deposited on rigid substrate 10provided with gate electrode 21 and gate scanning line 22 by chemicalvapor deposition; and second metal layer 50 is deposited by physicalvapor deposition. In the implementation, the material of gate insulatinglayer 30 comprises at least one of silicon oxide (SiO_(x)) and siliconnitride (SiN_(x)). The silicon oxide (SiO_(x)) comprises siliconmonoxide (SiO), silicon dioxide (SiO₂) or silicon oxide with othervalence states. The material of gate insulating layer 30 can also beprepared from other inorganic materials. The gate insulating layer 30prepared from SiO_(x), SiN_(X) and other inorganic materials can play arole in protecting and keeping gate electrode 21 or gate scanning line22 being insulated. The material of the second metal layer 50 comprisesat least one of copper, aluminum, neodymium, chromium, molybdenum,titanium and silver. Optionally, the material of the second metal layer50 can be copper, silver, or titanium, or the like. The material of thesecond metal layer 50 can also be copper-aluminum alloy,aluminum-neodymium alloy copper-molybdenum alloy, copper-titanium alloyor silver-molybdenum alloy, or the like. The material of the secondmetal layer 50 and the first metal layer may be the same or different.By continuously and sequentially depositing gate insulating layer 30,active layer 40, and second metal layer 50, a good interlayer contactcan be formed among the above three layers, thus reducing interfacestate density and improving product quality.

In the implementation, active layer 40 comprises a first amorphoussilicon film and a second amorphous silicon film sequentially stacked ongate insulating layer 30, and the first amorphous silicon film isdisposed between the gate insulating layer and the second amorphoussilicon film. The material of the first amorphous silicon film comprisesamorphous silicon (a-Si); and the material of the second amorphoussilicon film comprises impurity ion-doped amorphous silicon (n+a-Si).Further, optionally, the amorphous silicon comprises hydrogenatedamorphous silicon; the impurity ion-doped amorphous silicon comprisesphosphorus-doped amorphous silicon. In the implementation, the firstamorphous silicon film serves as a semiconductor layer, the secondamorphous silicon film can serve as an ohmic contact layer to reduce thecontact resistance between the source and/or the drain and the firstamorphous silicon film, and to improve product performance.

As shown in FIG. 4, at S30, photoresist is deposited on the rigidsubstrate provided with the second metal layer obtained at S20 using asecond mask process and patterned to form first photoresist layer 61 andsecond photoresist layer 62 by coating, exposal, development, etching,and stripping processes using a mask in three grayscales. Firstphotoresist layer 61 has three or more thickness variations andcomprises first-stage photoresist layer 611, second-stage photoresistlayer 612 and third-stage photoresist layer 613. The thickness offirst-stage photoresist layer 611, second-stage photoresist layer 612and third-stage photoresist layer 613 disclosed herein increasessequentially, that is, the thickness of second-stage photoresist layer612 is larger than that of first-stage photoresist layer 611, and thethickness of third-stage photoresist layer 613 is larger than that ofsecond-stage photoresist layer 612. First-stage photoresist layer 611 isdisposed in the middle of first photoresist layer 61 and a concave-likechannel is formed. In the implementation, first-stage photoresist layer611 is disposed in the middle of second-stage photoresist layer 612;first-stage photoresist layer 611 in the middle portion has a minimumthickness, thereby forming a groove structure and forming a channel (seethe dotted circle in FIG. 4). Optionally, first-stage photoresist layer611 can be disposed between second-stage photoresist layer 612 andthird-stage photoresist layer 613. In the implementation, the thicknessof second photoresist layer 62 spaced from first photoresist layer 61 islarger than that of second-stage photoresist layer 612. Optionally, thethickness of second photoresist layer is equal to the thickness of thethird-stage photoresist layer. Second photoresist layer 62 can bedisposed on gate scanning line 22, and stacked on the surface of secondmetal layer 50.

As shown in FIG. 5, at S40, a further etching is performed on a regionof the rigid substrate provided with first photoresist layer 61 andsecond photoresist layer 62, where the region is uncovered by firstphotoresist layer 61 and second photoresist layer 62. The process of thefurther etching comprises etching the region of second metal layer 50which is not covered by first photoresist layer 61 and secondphotoresist layer 62, and then sequentially etching the exposed activelayer 40 and gate insulating layer 30 below second metal layer 50 toexpose rigid substrate 10. First photoresist layer 61 disclosed hereincomprises first-stage photoresist layer 611, second-stage photoresistlayer 612 and third-stage photoresist layer 613. The etched second metallayer 50 comprises electrode layer 51 and data line layer 52. The etchedactive layer 40 comprises first active layer 41 and second active layer42. The etched gate insulating layer 30 comprises first gate insulatinglayer 31 and second gate insulating layer 32. Optionally, in theimplementation, a region of second metal layer 50 (see FIG. 4) that isuncovered by photoresist material (including first photoresist layer 61and second photoresist layer 62) is etched by wet etching process usingwet etching reagent; and the exposed active layer 40 and gate insulatinglayer 30 are etched by dry etching (see FIG. 4). The wet etching processhas the advantages of good selectivity, good repeatability, low cost,and high production efficiency. The dry etching process has goodanisotropy and can transfer photolithography patterns with highfidelity. In the implementation, since the wet etching reagent partiallypenetrates during the etching process of second metal layer 50 by wetetching process, the cross-sectional width (parallel to the direction ofrigid substrate 10) of the etched electrode layer 51 is smaller thanthat of first photoresist layer 61; the cross-sectional width of dataline layer 52 is smaller than that of second photoresist layer 62.

Referring to FIG. 5 and FIG. 6 together, at S50, rigid substrate 10provided with first photoresist layer 61 and second photoresist layer 62is ashed to remove first-stage photoresist layer 611; wherein both firstphotoresist layer 61 and second photoresist layer 62 are reduced by thethickness of first-stage photoresist layer 611; the exposed electrodelayer 51 is then etched by wet etching process to expose first activelayer 41; and source 511 and drain 512 are obtained. Referring to FIG.7, first active layer 41 is further partially etched by dry etchingprocess to form a conductive channel a (as shown in the dotted circle inFIG. 7). First active layer 41 comprises a first amorphous silicon filmand a second amorphous silicon film sequentially stacked on first gateinsulating layer 31. The first amorphous silicon film and the secondamorphous silicon film have been described in above S20, and are notdescribed in this implementation. The partial etching refers to etchingaway the second amorphous silicon film of first active layer 41 in theconductive channel a, and retaining the first amorphous silicon film offirst active layer 41. A region of first active layer 41, which is incontact with source 511 and drain 512, also remains the second amorphoussilicon film. Therefore, an ohmic contact can be formed between source511, drain 512 and first active layer 41 to improve the performance ofthe final product.

In this implementation, after first photoresist layer 61 is removed awaythe first-stage photoresist layer, second-stage photoresist layer 612and third-stage photoresist layer 613 are left. The second-stagephotoresist layer 612 disclosed herein is formed into two parts due tothe first-stage photoresist layer disposed in the middle portion beingashed. Since the partial ashing is performed on the photoresist materialdisposed on the entire surface of the rigid substrate, all of thesecond-stage photoresist layer 612, third-stage photoresist layer 613,and second photoresist layer 62 are uniformly reduced by the thicknessof the first-stage photoresist layer that is ashed in the ashingprocess; and the original first-stage photoresist layer is alsocompletely removed by subtracting its own thickness and electrode layer51 below it is exposed. In this implementation, the first photoresistlayer and the second photoresist layer are patterned by photoresistmaterial. The photoresist material comprises organic photoresistmaterial. Specifically, the photoresist material comprises a resin, asensitizer, and a solvent. The photoresist material may further compriseother materials without limitation.

Since the remaining second-stage photoresist layer 612, third-stagephotoresist layer 613 and second photoresist layer 62 on the surface ofrigid substrate 10 provided with source 511 and drain 512 aresimultaneously reduced by the thickness of first-stage photoresist layerin the above step S50, the above second-stage photoresist layer 612,third-stage photoresist layer 613 and second photoresist layer 62 arefurther ashed at S60 to remove second-stage photoresist layer 612; andthird-stage photoresist layer 613 and second photoresist layer 62 aresimultaneously reduced by the thickness of second-stage photoresistlayer 612 again, as shown in FIG. 8. The remaining third-stagephotoresist layer 613 is partially covered on the surface of drain 512although its thickness is reduced again; second photoresist layer 62still covers the surface of data line layer 52 after the ashing processbecause its thickness is greater than that of second-stage photoresistlayer 612. In this step, as shown in FIG. 9, the depositing apassivation layer as a whole comprises: continuing depositing on oneside surface of the rigid substrate with various layers of structure hasbeen deposited (including the gate insulating layer, the active layer,etc.) and forming passivation layer 70. Since the surface of rigidsubstrate 10 after the above steps S10-S50 is not flat and there is acertain structural difference, it can be seen from the cross-sectionalschematic view shown in FIG. 9 that passivation layer 70 comprises fourportions, which are first passivation layer 71, second passivation layer72, and third passivation layer 73 and fourth passivation layer 74,respectively. The region covered by first passivation layer 71 comprisessource 511, drain 512, third-stage photoresist layer 61 and a partiallyexposed first active layer 41; and one side of an exposed first gateinsulating layer 31, the first active layer 41 and source 511. In theimplementation, the drain may be partially covered with the third-stagephotoresist layer, or may be entirely covered with the third-stagephotoresist layer when the surface of the drain is partially coveredwith the third-stage photoresist layer, the region of the surface of thedrain uncovered by the third-stage photoresist layer may be directlycovered with a passivation layer (such as the first passivation layer).Second passivation layer 72 and fourth passivation layer 74 cover thesurface of the exposed rigid substrate 10, which is on both sides ofgate scanning line 22. Third passivation layer 73 covers the surface ofsecond photoresist layer 62. The material of the passivation layercomprises at least one of silicon nitride (SiN_(x)), silicon monoxide(SiO) and silicon dioxide (SiO₂). The passivation layer can play a rolein protecting a thin film transistor, a data line layer and a gatescanning line, and has a certain resistance to oxygen and water vapor,and has an insulating effect.

At S70, the remaining third-stage photoresist layer 613 and secondphotoresist layer 62 are stripped; when third-stage photoresist layer613 and second photoresist layer 62 are stripped, a portion of the firstpassivation layer covered on the third-stage photoresist layer, thethird passivation layer covered on the second photoresist layer areremoved together as shown in FIG. 10; original first passivation 71 (seeFIG. 9) becomes a new passivation layer 711, and a portion of drain 512is partially exposed. After cleaning and drying, the transparentconductive material is then physically vapor deposited to form atransparent conductive layer, and the transparent conductive layer ispatterned to form pixel electrode 81 and common electrode 82 as seen inFIG. 11 using a third mask process by coating, exposal, development,etching, and stripping processes. There is a direct contact connectionregion between pixel electrode 81 and drain 512, and one end of drain512 is covered with the pixel electrode; compared with the case wherethe pixel electrode is connected to the drain through via-holes, thearrangement can fundamentally avoid the problem of disconnection of thepixel electrode, and is beneficial to improve the yield of the productwhile simplifying the process. The drain is exposed by stripping thethird-stage photoresist layer, thereby facilitating the deposition andpreparation of the transparent conductive layer. The pixel electrode 81extends until passivation layer 711 and second passivation layer 72 arepartially covered while covering the exposed drain 512; and the pixelelectrode also play a role in protecting drain 512 and active layer 41,or the like, and can prevent the erosion of oxygen or water vapor in theair. Data line layer 52, second active layer 42 and second gateinsulating layer 31 are covered by common electrode 82. When thecross-sectional width of gate scanning line 22 is larger than the widthof second gate insulating layer 31, and the gate scanning line 22 ispartially exposed, common electrode 82 can also extend and cover theexposed gate scanning line 22, and a bridging between gate scanning line22 and data line layer 52 can be achieved, which is beneficial to theline layout of the subsequent display panel. Referring to FIG. 5, it ismore convenient to realize the connection between the gate scanning lineand the common electrode in the subsequent etching process by making thecross-sectional width L of the second photoresist layer smaller than thecross-sectional width H of the gate scanning line. Common electrode 82can also prevent oxidation of metal electrodes (such as data line layer52, gate scanning line 22, etc.), which are directly exposed to theatmosphere, and have a certain protective effect. In the implementation,second gate insulating layer 32 and second active layer 42 are disposedbetween gate scanning line 22 and data line layer 52.

Cleaning or annealing process is also included in S70 withoutlimitation. The material of the transparent conductive layer comprisesat least one of indium tin oxide, indium oxide zinc, aluminum zinc oxideand indium gallium zinc oxide. Optionally, the depositing method furthercomprises magnetron sputtering, chemical vapor deposition, etc.

In the implementation, the transparent conductive layer covering theouter side may also serve as a second electrode for storage ofcapacitance, and constitutes an upper and lower electrode for storage ofcapacitance together with the first electrode formed by patterning thefirst metal layer a passivation layer can be disposed between the firstelectrode and second electrode.

Cleaning, annealing or detecting operation may be included in themanufacturing method of the TFT array substrate without limitation, andspecific experimental parameters during the process of S10-S70 are notexcessively limited in the implementation. A total of three maskprocesses were used during the process of S10-S70, which greatlysimplifies the process flow, drastically improves the productivity andutilization of equipments, and reduces unit cost. Moreover, themanufacturing method of the implementation has a simple process and canrealize large-scale industrial production.

Another implementation further provides a manufacturing method of a TFTarray substrate comprising:

S210: providing a rigid substrate, depositing a first metal layer on therigid substrate, and patterning the first metal layer to form a gateelectrode and a gate scanning line;

S220: depositing sequentially a gate insulating layer, an active layerand a second metal layer on the gate electrode and the gate scanningline;

S230: coating photoresist on the second metal layer and patterning thephotoresist to form a first photoresist layer and a second photoresistlayer; wherein the first photoresist layer comprises a first-stagephotoresist layer, a second-stage photoresist layer and a third-stagephotoresist layer; the thickness of the second-stage photoresist layeris larger than that of the first-stage photoresist layer, and thethickness of the third-stage photoresist layer is larger than that ofthe second-stage photoresist layer; the first-stage photoresist layer isdisposed in the middle of the first photoresist layer and a channel isformed; and the thickness of the second photoresist layer is larger thanthat of the second-stage photoresist layer;

S240: etching a region of the second metal layer that is outside thechannel and uncovered by the first photoresist layer and the secondphotoresist layer to expose the active layer, and performing ashingtreatment on the first photoresist layer and the second photoresistlayer to remove the first-stage photoresist layer;

S250: etching a region of the exposed active layer and a region of thegate insulating layer, which are outside the channel to expose the rigidsubstrate, and forming a source electrode and a drain electrode byetching;

S260: performing ashing treatment on the first photoresist layer and thesecond photoresist layer to remove the second-stage photoresist layer,and then depositing a passivation layer as a whole;

S270: stripping the third-stage photoresist layer and the secondphotoresist layer, and depositing a transparent conductive layer andpatterning the transparent conductive layer to form a pixel electrodeand a common electrode.

The difference between this implementation and the previousimplementation is that there is a difference in the stage of operationsof performing the ashing treatment on the first photoresist layer andthe second photoresist layer to remove the first-stage photoresist layerfor the first time at S240 in this implementation. In thisimplementation, the operation of performing ashing treatment on thefirst photoresist and the second photoresist is after the operation ofetching a region of the second metal layer that is outside the channeland uncovered by the first photoresist layer and the second photoresistlayer. As shown in FIG. 12, after etching a region of the second metallayer that is outside the channel and uncovered by the first photoresistlayer and the second photoresist layer, an ashing treatment is thenperformed on the first photoresist layer and the second photoresistlayer to remove the first-stage photoresist layer. Next, a region of theexposed active layer 40 and a region of the exposed gate insulatinglayer 30 that are outside the channel are etched, and the exposed secondmetal layer in the channel (specifically, the electrode layer 51) due tothe removal of first-stage photoresist layer 611 by the ashing processis then etched, and etching is continued to form source electrode 511and drain electrode 512.

Further optionally, the operation of performing the ashing treatment onthe first photoresist and the second photoresist can be performed afterthe operation of etching a region of the second metal layer and a regionof the active layer that are outside the channel and uncovered by thefirst photoresist layer and the second photoresist layer.

As shown in FIG. 11, the implementation further provides a TFT arraysubstrate; the TFT array substrate comprises rigid substrate10, gateelectrode 21 and gate scanning line 22 stacked on rigid substrate 10;and gate insulating layer 31, an active layer (comprising first activelayer 41 and second active layer 42), source electrode 511, drainelectrode 512, data line layer 52, passivation layer 71, pixel electrode81 and common electrode 82 stacked sequentially on gate electrode 21 andgate scanning line 22. One side of drain electrode 512 is covered withpixel electrode 81; second gate insulating layer 32 and second activelayer 42 are disposed between gate scanning line 22 and data line layer52; gate scanning line 22 and data line layer 52 are respectivelyconnected with common electrode 82.

It should be noted that those skilled in the art can make some changesand modifications to above implementations according to the disclosureand depiction of the foregoing description. Therefore, the presentdisclosure is not limited to the specific embodiments disclosed anddescribed above, and some of equivalent modifications and changes madeto the present disclosure should also be within the protection scope ofthe claim of the present disclosure.

What is claimed is:
 1. A manufacturing method of a TFT array substratecomprises: providing a rigid substrate, depositing a first metal layeron the rigid substrate, and patterning the first metal layer to form agate electrode and a gate scanning line; depositing sequentially a gateinsulating layer, an active layer and a second metal layer on the gateand the gate scanning line; coating photoresist on the second metallayer and patterning the photoresist to form a first photoresist layerand a second photoresist layer; wherein the first photoresist layercomprises a first-stage photoresist layer, a second-stage photoresistlayer and a third-stage photoresist layer; the thickness of thesecond-stage photoresist layer is larger than that of the first-stagephotoresist layer, and the thickness of the third-stage photoresistlayer is larger than that of the second-stage photoresist layer; thefirst-stage photoresist layer is disposed in the middle of the firstphotoresist layer and a channel is formed; and the thickness of thesecond photoresist layer is larger than that of the second-stagephotoresist layer; etching a region of the second metal layer, a regionof the active layer and a region of the gate insulating layer, which areoutside the channel and uncovered by the first photoresist layer and thesecond photoresist layer to expose the rigid substrate; performingashing treatment on the first photoresist layer and the secondphotoresist layer to remove the first-stage photoresist layer, andforming a source electrode, and a drain electrode by etching; performingashing treatment on the second-stage photoresist layer, the third-stagephotoresist layer and the second photoresist layer to remove thesecond-stage photoresist layer, and then depositing a passivation layeras a whole; stripping the third-stage photoresist layer and the secondphotoresist layer, and depositing a transparent conductive layer andpatterning the transparent conductive layer to form a pixel electrodeand a common electrode.
 2. The manufacturing method as claimed in claim1, wherein the active layer comprises a first amorphous silicon film anda second amorphous silicon film sequentially stacked on the gateinsulating layer, and the first amorphous silicon film is disposedbetween the gate insulating layer and the second amorphous silicon film.3. The manufacturing method as claimed in claim 2, wherein the materialof the first amorphous silicon film comprises amorphous silicon and thematerial of the second amorphous silicon film comprises impurityion-doped amorphous silicon.
 4. The manufacturing method as claimed inclaim 2, wherein the process of forming the source electrode and thedrain electrode by etching comprises: etching the second metal layerafter ashing the first-stage photoresist layer; the method furthercomprises etching the second amorphous silicon film to form source,drain, and conductive channel regions.
 5. The manufacturing method asclaimed in claim 1, wherein a data line layer is formed from the secondmetal layer covered by the second photoresist layer after etching theregion of the second metal layer, the region of the active layer and theregion of the gate insulating layer, which are outside the channel anduncovered by the first photoresist layer and the second photoresistlayer.
 6. The manufacturing method as claimed in claim 5, wherein thegate scanning line and the data line layer are bridged through thecommon electrode.
 7. The manufacturing method as claimed in claim 1,wherein the material of the transparent conductive layer comprises atleast one of indium tin oxide, indium oxide zinc, aluminum zinc oxideand indium gallium zinc oxide.
 8. The manufacturing method as claimed inclaim 1, wherein the material of the passivation layer comprises atleast one of silicon oxide and silicon nitride.
 9. The manufacturingmethod as claimed in claim 1, wherein the material of the first metallayer comprises at least one of copper, aluminum, neodymium, chromium,molybdenum, titanium and silver.
 10. The manufacturing method as claimedin claim 1, wherein the material of the second metal layer comprises atleast one of copper, aluminum, neodymium, chromium, molybdenum, titaniumand silver.
 11. A TFT array substrate prepared by the manufacturingmethod as claimed in claim
 1. 12. The TFT array substrate as claimed inclaim 11, wherein the active layer comprises a first amorphous siliconfilm and a second amorphous silicon film sequentially stacked on thegate insulating layer, and the first amorphous silicon film is disposedbetween the gate insulating layer and the second amorphous silicon film.13. The TFT array substrate as claimed in claim 12, wherein the materialof the first amorphous silicon film comprises amorphous silicon and thematerial of the second amorphous silicon film comprises impurityion-doped amorphous silicon.
 14. The TFT array substrate as claimed inclaim 12, wherein the process of forming the source electrode and thedrain electrode by etching comprises: etching the second metal layerafter ashing the first-stage photoresist layer; the method furthercomprises etching the second amorphous silicon film to form source,drain, and conductive channel regions.
 15. The TFT array substrate asclaimed in claim 11, wherein a data line layer is formed from the secondmetal layer covered by the second photoresist layer after etching theregion of the second metal layer, the region of the active layer and theregion of the gate insulating layer, which are outside the channel anduncovered by the first photoresist layer and the second photoresistlayer.
 16. The TFT array substrate as claimed in claim 15, wherein thegate scanning line and the data line layer are bridged through thecommon electrode.
 17. The TFT array substrate as claimed in claim 11,wherein the material of the transparent conductive layer comprises atleast one of indium tin oxide, indium oxide zinc, aluminum zinc oxideand indium gallium zinc oxide.
 18. The TFT array substrate as claimed inclaim 11, wherein the material of the passivation layer comprises atleast one of silicon oxide and silicon nitride.
 19. A display panel,wherein the display panel comprises a TFT array substrate prepared bythe manufacturing method as claimed in claim 1.